1. Field of the Invention
The invention relates generally to a method of manufacturing a semiconductor device utilizing a gate dielectric film. More particularly, the present invention relates to a method of manufacturing a semiconductor device capable of improving a leakage current characteristic of a gate dielectric film, while increasing its dielectric constant, applied to a high-speed high-density logic device and an ultra high integration device of more than 1G DRAM class, which utilize a high dielectric material as a gate dielectric film.
2. Description of the Prior Art
In general, a gate dielectric film of DRAM devices presently mass-produced and of a logic device in a semiconductor device is used by growing SiO2 by means of annealing process or rapid thermal process. As the design rule is scaled down, a SiO2 gate dielectric film is scaled down to 25xcx9c30 xc3x85 being a limit to the tunneling effect. It is expected that the gate dielectric of 0.10 xcexcm technology will result in 30xcx9c40 xc3x85 in thickness. Due to off-current by the tunneling of the gate dielectric film, however, there is a possibility that the static power consumption is increased and its operation performance is adversely affected. Particularly, in case of a memory device, a scheme to reduce a leakage current becomes an important issue. As a part of efforts to overcome this, a research for adopting a dielectric material having a high dielectric constant as a gate dielectric film has been carried out.
Recently, research for using dielectric materials such as TiO2, Al2O3, etc. as a gate dielectric film has been actively carried out. Al2O3 has a dielectric constant of 8xcx9c15, which is larger about 2.5 times than the dielectric constant of a thermal oxide film, and has a good leakage current characteristic. However, there is a problem that Al2O3 is utilized as a gate dielectric film since its dielectric constant is degraded depending on its thickness in controlling the thickness (Tox) of the effective oxide film to below 25xcx9c30 xc3x85. Also, it is reported that TiO2 has a high dielectric constant of 25xcx9c40. However, there is a problem that TiO2 is utilized as a gate dielectric film since its leakage current characteristic is poor.
It is therefore an object of the present invention to provide a method of manufacturing a semiconductor device capable of improving a leakage current characteristic of a gate dielectric film, while increasing its dielectric constant, applied to a high-speed high-density logic device and an ultra high integration device of more than 1G DRAM class which utilize a high dielectric material as the gate dielectric film.
In order to accomplish the above object, a method of manufacturing a semiconductor device according to the present invention is characterized in that it comprises the steps of depositing a Ti1xe2x88x92XAlXN film on a semiconductor substrate; oxidizing the Ti1xe2x88x92XAlXN film by oxidization process to form a (Al2O3)Xxe2x80x94(TiO2)1xe2x88x92X gate dielectric film; and forming a gate electrode on the (Al2O3)Xxe2x80x94(TiO2)1xe2x88x92X gate dielectric film.